Systems and methods herein generally relate to controlling printer operations and more particularly to using electrostatic sensors, potentially in combination with optical sensors, to control printer settings.
Printers deal with many different input items and adjust for changes in printing operations over time. One process of adjusting the settings of the printer is referred to as adjusting the tone reproduction curve (TRC). The TRC calls for different amounts of different colors to be used in different situations.
Many printers use optical sensors to test printing and adjust the TRC. These optical sensors, commonly called automatic density sensors (ADC), work by shining light on a toner patch on a photoreceptor or intermediate transfer belt (ITB) and recording the specular and diffuse reflections. Depending on the type of toner and/or sensor, either one of the reflections or a combination of both, are used to generate an optical signal. The sensitivity of the optical signal to changes of toner mass on the photoreceptor or ITB is low for solid patches of toner, but increases for less dense (e.g., halftone) patches.
Therefore, some printers use several halftone patches to adjust the TRC for halftones and interpolate the setting for the solid patch. This interpolation can lead to solid densities being out of control and can vary widely. Solid densities become dependent on several variables that can affect development, such as tribo charge of the toner, toner age, environmental conditions etc.